The present invention relates to optical fiber connectors and, more particularly, to a buffer adapter, also known as the boot, of an optical fiber connector which provides the connector with anti-snagging characteristics and enables the polarity of an optical fiber cable terminated by the connector to be ascertained.
In networks and communication equipment that utilize a high count of optical fibers, such as with a dense wavelength division multiplexer (DWDM), it is frequently a nuisance and time consuming to de-tangle the optical connectors for desirable proper order and illustration, and to ensure DWDM operation, it is important to ensure that the 40 output fibers can also be organized, for example, in order of increased wavelengths, and detangled without damage to the fibers. An increasingly used connector for the purpose of determining fibers on DWDMs is known as the behind-the-wall (BTW) version of the LC connector. This small-form-factor-connector (SFFC) is an optical connector, such as is shown in U.S. Pat. No. 5,719,977 which discloses a BTW optical fiber connector for terminating a cable containing a buffered optical fiber. Each optical fiber is held within a fiber-holding assembly comprising a ferrule and a spring-loaded base member. The fiber-holding assemblies are contained within a common housing that is formed to include a flexible molded plastic latching arm member for interlocking with a mating receptacle or adapter. In high-density applications it is possible to have the latch xe2x80x9cfish-hookxe2x80x9d other connectors which become difficult to separate and organize.
Similarly, it can be important that when only a pair of transmit and receive optical fibers are to be connected to another pair of transmit and receive optical fibers, the correct optical fibers of each of the pairs are connected together in a duplex format, or optically coupled at their ends. Otherwise, an end of a transmit optical fiber of one pair may be connected to an end of a receive optical fiber of the other pair, which, for obvious reasons, is unacceptable. Properly orienting the optical fibers in this duplex manner ensures that the optical fibers are connected with the proper polarity.
Duplex optical connectors have been utilized in the communications industry to couple two simplex optical fibers together in a duplex arrangement to allow both optical fibers to be simultaneously connected to ports located on communication equipment or to an adapter that connects pairs of optical fibers together. For example, U.S. Pat. No. 4,787,706 discloses a duplex optical fiber connector for terminating a cable containing a pair of buffered optical fibers. The optical fibers are held within fiber-holding assemblies which are contained within a common housing that is formed to include two flexible molded plastic side arm members for interlocking with a mating receptacle. The housing includes details that can be used to ensure that when the optical fiber connector is connected with another optical fiber connector, the connection is made with the properly polarity.
U.S. Pat. No. 5,579,425 (hereinafter the ""425 patent) also discloses an optical fiber duplex connector which is constructed by joining together a pair of simplex connectors with a plastic clip. The plastic clip has information thereon, such as the letters A and B, that may be utilized by a user to identify the correct polarization of the duplex connector with respect to an adapter (not shown) into which it is plugged.
Although the plastic clip disclosed in the ""425 patent is suitable for use with the type of simplex connectors shown, which are normally connected to the front side of a connector receptacle or adapter, this clip is generally not suitable for use with behind-the-wall (BTW) connectors. BTW connectors which typically use buffered fibers are connected on the back side, commonly referred to as the junior side, of the receptacle or adapter where there is typically very little room. The confined area dictates that the simplex connectors and the boots associated therewith generally be shorter in length than the boots of the cables that are used with the simplex connectors in front side mounting configurations.
On the front side of the connector receptacle or adapter, there is generally plenty of space for the length of the connector which usually is for jumper cordage and the boot, which is also referred to as a cable support, and hence is not an issue. Therefore, the plastic clip disclosed in ""425 patent, which connects to the housing of the connectors is suitable for use in this type of environment since the lengths of the housings normally are sufficiently long to accommodate connection with the clip at locations near the back ends of the housings. However, this generally is not true with respect to connectors used in BTW configurations.
It is important that the simplex or duplex orientation is maintained, i.e, each connector not be allowed to rotate on fiber axis, so that the trigger on the boot is in the proper orientation to interact with the latch. Internal keys added to the boot that fit into existing key-slots in the extender cap accomplish this. These key-slots are provided for inspection of proper orientation of the extender cap in the plug housing.
In BTW mounting configurations, the connectors that terminate the ends of the receive and transmit optical fibers must be connected to the receive and transmit ports located in the junior side of the receptacle or adapter. Therefore, the receive and transmit optical fibers must be correctly polarized on the junior side of the housing in the same manner in which the receive and transmit optical fibers must be correctly polarized on the front side of the receptacle or adapter. However, currently there is no aid for assisting a user or technician in determining the polarity of the optical fibers connected on the junior side. Therefore, once the transmit and receive optical fibers have been connected to the ports on the junior side, if a user removes one or both of the optical fibers from their respective ports, the user must somehow keep track of which simplex connector is to be connected to which port in order to ensure that the connectors are properly polarized when they are re-connected to the transmit and receive ports.
It would be desirable to provide a duplex boot that converts two simplex connectors into a duplex connector for use in case where there is very little room to work with the connectors and/or in cases where the housings of the connectors are too short to enable the housings to be coupled together to form a duplex connector. For example, once the connector has been inserted into an associated adapter or receptacle, most of the body of the connector is contained within the adapter or receptacle and is generally of insufficient length to enable a duplex yoke to be attached thereto for the purpose of clipping two of the connectors together to form a duplex connector.
Accordingly, a need exists for simplex and duplex boots that are capable of providing an anti-snag mechanism that prevents the simplex or duplex connectors from fish-hooking when the connectors are being removed from a connection location, and a means to prevent rotation of the connector on the fiber axis. Additionally, a need exists to join two simplex connectors together to form a duplex connector, which is suitable for use with connectors used in BTW configurations, and which helps a user to determine the polarity of the connectors easily.
The present invention is an anti-snag boot that attaches to the extender cap of an optical fiber BTW simplex connector to provide the connector with anti-snagging characteristics and/or to enable the polarity of an optical fiber cable terminated by the connector to be ascertained. The device generally is a boot having internal keys that are adapted to be received in the key-slots of the extender cap and prevent rotation of the connector within the boot of an optical fiber simplex or duplex connectors. The boot has a trigger thereon that is in contact with the latch of the simplex connector when the simplex connector is held in the clip body. When a user depresses the trigger, the trigger depresses the latch and causes the simplex connector to be decoupled from an adapter or receptacle. The trigger prevents the latch from snagging on objects, or xe2x80x9cfish-hookingxe2x80x9d, when the simplex connector is being moved.
In accordance with a first embodiment, the boot is adapted to receive and grip the outer surface of the extender cap of a single simplex connector. A generally cylindrical bore is formed in the boot and the inner surface of the bore contains keys which are adapted to interact with existing key-slots of the extender caps. A cable can be passed through the boot prior to assembly of the connector. The boot is aligned and attached to a simplex connector, and then the trigger is available when it is desired to couple or decouple the connector from the receptacle or adapter. The boot has a trigger thereon that is in contact with the latch of the simplex connector when the simplex connector is held by the boot. The trigger allows a user to decouple the connector from an adapter or receptacle and provides the connector with the aforementioned anti-snagging feature.
In accordance with another embodiment, the device is a duplex boot that comprises a trigger that is adapted to receive and interact with the latch of the connector housing, that can also contain a web to create a duplex boot from a pair of simplex connectors both to hold the simplex connectors in close spatial proximity to one another to thereby form a duplex connector. The trigger and web are made integral with two or more boots to form a unitary structure. Slots are formed in the extender cap which interact with internal keys provided in the boots to provide an anti-rotation feature. During assembly of the connectors, cables can be passed through the boots so they can be later attached to (a pair of) simplex connectors when the simplex connectors are coupled to or decoupled from a receptacle or adapter. The duplex boot has markings thereon, which preferably are located on the trigger, that enable the polarity of the cables held in the connectors to be easily ascertained.